package com.x.epspace.common;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;


public class CodeUtil {
	static public void createCode(HttpSession session,ServletOutputStream out,String codename) throws Exception{    
        // 在内存中创建图象
        int width=85, height=25;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        // 获取图形上下文
        Graphics g = image.getGraphics();

        //生成随机类
        Random random = new Random();

        // 设定背景色
        g.setColor(getRandColor(200,250));
        g.fillRect(0, 0, width, height);

        //设定字体
        g.setFont(new Font("Times New Roman",Font.PLAIN,20));

        //画边框
        //g.setColor(new Color());
        //g.drawRect(0,0,width-1,height-1);


        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
        g.setColor(getRandColor(160,200));
        for (int i=0;i<155;i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x,y,x+xl,y+yl);
        }

        // 取随机产生的认证码(4位数字)
        String sRand="";
        String[] strTable = {"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f","g","h","i","j","k","m","n","p","q","r","s","t","u","v","w","x","y","z"};
        for (int i=0;i<6;i++){
            //String rand=String.valueOf(random.nextInt(10));
        	String rand= strTable[random.nextInt(34)];
            sRand+=rand;
            // 将认证码显示到图象中
            g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            g.drawString(rand,13*i+6,16);
        }

        // 将认证码存入SESSION
        session.setAttribute(codename,sRand);
        // 图象生效
        g.dispose();
        ServletOutputStream responseOutputStream =out;
        // 输出图象到页面
        ImageIO.write(image, "JPEG", responseOutputStream);
        

        //以下关闭输入流！
        responseOutputStream.flush();
        //responseOutputStream.close();

	}
	
	 static Color getRandColor(int fc,int bc){//给定范围获得随机颜色
	        Random random = new Random();
	        if(fc>255) fc=255;
	        if(bc>255) bc=255;
	        int r=fc+random.nextInt(bc-fc);
	        int g=fc+random.nextInt(bc-fc);
	        int b=fc+random.nextInt(bc-fc);
	        return new Color(r,g,b);
	    }


}
